Series parallel switching apparatus



Oct. 9, 1956 H. w. GRAYBILL l 2,756,335

SERIES PARALLEL swITcHING APPARATUS Filed May 25, 1953 5 Shets-Sheet 1 Oct. 9, 1956 H. W. GRAYBILL 2,766,335

SERIES PARALLEL SWITCHING APPARATUS Oct. 9,' 1956 H. w. GRAYBILI. 2,766,335

SERIES PARALLEL SWITCHING APPARATUS Filed may 25, 1955 5 sheetsneet :s

s Gmlmluml Oct. 9, 1956 H. W. GRAYBILL SERIES PARALLEL SWITCHING APPARATUS Filed May 25. 1953 fd f4 5 Sheets-Sheet 4 y Oct. 9, 1956 Filed May 25, 1955 H. W. GRAYBILL SERIES PARALLEL SWITCHING APPARATUS 5 Sheets-Sheet 5 .Il E- 5.

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United States Patent O 2,766,33s SERIES PARALLEL -sWrrCHrNG APPARATUS Howard W. Graybill, "Greensburg, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa.

My invention relates to high current switches for use in the buses feeding an electric furnace and is more particularly directed to a novel arrangement for switching from series to parallel or the reverse for the connections of transformer secondary windings to an electric furnace.

In graphitizing furnace operation, it is common practice to use a furnace transformer with a plurality of secondary windings.

When furnace operation is commenced, the resistance of the material therein is high and hence it is necessary to impress a large magnitude of Voltage, for example 240 volts, across the furnace terminals. For this purpose, the secondary windings are connected in parallel groups with two windings in series in each group.

As the resistance of the furnace load decreases, the secondary voltage is decreased, for example to 120 volts. This is done by opening a primary circuit breaker and reconnecting the secondary windings so that they are in parallel. The primary circuit breaker is then closed and the voltage of each parallel connected secondary winding is impressed on the furnace terminals.

In the prior art arrangement, the series to parallel switch construction consisted of four inter-leaved bus bars, each of opposite polarity for two secondary windings. The inner two bus bars had link connecting portions which could alternately be bolted in alignment with the interleaved buses so as to connect the secondary windings in parallel.

The switching operation from a parallel to series connection required that the main protective circuit breaker be open and then an operator unbolt the links at the load end and loosen the bolts at the source hinge end, rotate the two links about the hinge end into a second plane and there rebolt the links together. After this operation was completed, the main circuit breaker could again be closed and the secondary winding would be connected in series.

This prior art arrangement has many disadvantages which are overcome by my instant invention. A few of the disadvantages are as follows:

1. Since the switching operation requires the bolting and unbolting of a large number of links, the lost production time, when the main circuit breaker was open during this operation, is of the order of a half hour to two hours.

2. The volume of space required by the unit is rather large since the connecting links had to be rotated from a first plane to a second plane and represented a distinct disadvantage in the installation where limited space is available. l

3. Separate and independent means have to be provided to support the links when they are rotated into the second plane and additional means must be provided to insulate this support unit from ground.

4. Itis impossible to provide an interlock unit for this type of switch and hence, no practical means have been Patented Oct. 9, 1956 devised for insuring that the line will not be energized while the operator is connecting or disconnecting bolts during switching operation.

5. Since the open contacts are exposed to the atmosphere and do not have wiping action, it is necessary to periodically clean the contacts with emery cloth or steel wool to remove the oxide film.

6. In the type of installation which supplies electrical energy to graphitizing furnaces, the nter-leaved bus bars carry current magnitudes that run on the order of 30,000 to 60,000 amperes. Hence, it is essential to maintain the bus reactance at a minimum. However, in the prior art arrangement, the series connection require that the linking members be rotated into a second plane thereby inducing and increasing reactance in spite of the inter-leaved bus structure.

7. The quality or pressure of the electrical joint is dependent on a function of the human element. Thus, for example, if an operator should fail to sufficiently tighten any one of the plurality of bolts on the link members, the associated electrical joint would under go excess heat and fail thereby causing extended loss of production time and costly repairs.

In the novel apparatus of my invention to achieve switching from parallel to series connections or vice versa is possible. I am able to overcome all of the above mentioned disadvantages of the prior art switch and am able to achieve many advantages thereover.

My novel series to parallel switching device incorporates bridge switching rather than knife switching as heretofore used in this type of switch.

By using the bridge switching concept, I am able to make a relatively compact unit so that all of the switch operation is confined to the volume encompassed by the interleaved bus bars and am also able to utilize standard switch equipment such as the low voltage high current switch disclosed in my copending application Serial No. 317,101, led October 27, 1952.

By utilizing the above mentioned type of low voltage high current switch or a switch unit utilizing the general concepts presented therein, I am able to achieve simultaneous operation of many groups of contacts to switch from a parallel connection to a series connection by turning a single handle or crank from its one extreme position to the other extreme position. By so doing, I also insure a high-pressure contact, in which the pressure is independent of the human element, and maintain a compact unit with minimum reactance.

Accordingly, one object of my invention is to provide a novel series parallel switching apparatus wherein all contacts operate simultaneously by one continuous motion of a single operating crank or hand wheel.

Another object of my invention is to provide a series parallel switching apparatus which is constructed in such a manner that all of the current carrying components are confined within the volume outlined by the interleaved bus arrangement.

Still another object of my invention is to provide a switch apparatus which can be shipped from its point of manufacture as a complete unit and which, together with its supporting rack, comprises a self-supporting free standing structure.

A still further object of my invention is to provide switching apparatus with interlocking means so that the contact of the switches therein cannot be engaged or disengaged until the source circuit is de-energized.

Another object of my invention is to provide bridge type switches for a series to parallel switching apparatus which have high pressure wiping action to provide cleaning and removal of the deposited oxide and sulphide lms on the cooperating contacts.

A still further object of my invention is to provide a series parallel switching apparatus with a plurality of cooperating contacts having high pressure contact which is independent of the speed of operation and entirely independent of the human elements `of operation.

A still further object of `my invention is to provide switching apparatus which can be utilized in an interleaved type of bus arrangement in which the current of adjacent bus bars flows in opposite directions so that the field `of the current in one bus neutralizes the eld of current in the other. My novel switching apparatus is so constructed `that it will not increase the bus reactance of the inter-leaved system as it is confined within the volume outlined thereby.

Another object of my invention is to provide a series parallel switching apparatus which has relatively quick operation to thereby keep lost production time during the switching operation at an absolute minimum.

Another object of my invention is to provide a series parallel switching apparatus which has a small amount of space requirement, requires relatively small amounts of copper, is low in cost, maintains the low reactance achieved by interlaced bus bar relationship and can be adapted with interlocking means to prevent operation under load to eliminate danger to personnel and equipmerit.

These and other `objects of my invention will be apparent from the following description when taken in connection with the drawings in which:

Figure l is a Ascheiriric perspective view illustration of the prior art series parallel switch. The dotted lines of this figure illustrate the `series connection and the movement of the links to a second plane thereby introducing additional reactance to the interlaced bus system.

Figure 2 is a schematic view showing a bridge concept of my invention of a novel series to parallel switching apparatus whereby all of the components can be confined Within the cubical elements of the interlaced bus bars.

Figure 3a and Figure 3b are schematic wiring diagrams showing the placement and location of the various switch units in a multiple secondary system used to supply a variable resistive load `such as an electrical furnace. Figure 3a shows the position of the switch units when the transformer secondary windings are connected in pai'- allel and Figure 3b illustrates the position of the switch units when the transformer secondary' windings are con nected in series.

Figure 4 is a view of my novel series to parallel switching apparatus las mounted and installed ready for connection to load and source units.

Figure 5a is a top view of my switching apparatus illustrating the interlaced buses and the manner in which a single control simultaneously operates all of the switch units.

Figure 5 b is a view taken in the direction of the arrows S17- 5b of Figure 5a and illustrates a side view of my novel switching apparatus.

Figure 5c is a view taken Sc-Sc of Figure 5b.

Figure 6 is a partial bottom view of my switching apparatus taken in the direction of the arrows 6-6 of Figure 5b.

Figure 7 is a top perspective view of my novel switch ing apparatus and illustrates the single control for the plurality of cooperating contacts and the `manner in which these units are confined within the volume outlined by the bus structure.

Figure 8 is an enlarged sectional View showing the switch units and inter-leaved bus bars which are to be connected to two secondary transformer windings for alternate parallel and series connections thereof. This figure illustrates the position of the switching unit when the switch apparatus connects the two secondary transformer windings in parallel.

in the direction of the arrows Figure 9 is a top view `of a modification of the apparatus shown in Figures 2 through 8. This figure illustrates tlie principle of my invention applied to an openclosed apparatus as distinguished from Aa series paralle apparatus.

Referring now to the figures, Figure l is a schematic perspective illustration showing the prior art arrangement for series to parallel switching.

The bus bas ,iti and 11 will be Connected to one secondary win g and the bus bars l2 and 13 to a second secondary winding. The right hand end of the bus bars will lead to the electrical terminals of an electric furnace. The outer bus bars it) and i3 extend straight through whereas the inner adjacent bus bars and l2 are in sections.

Link members 14 and serve to complete the second-- ary inner bus bars il and 12 when rotated into a plane of the bus bars 19, 1li and in this lower position, the links 14 and 15 respectively are bolted by the operator to the bus bars 1i and 12. rlhis connects the secondary windings in parallel. However, when it is necessary `to series connect the transformer secondaries, a main circuit breaker is opened and the operator removes the bolts, such as lo, which hold the links 1d and i5 to the bus bars 11 and 12, respectively, and also loosen the hinged bolt such as 1S. The links it@ and i5 are then rotated into a second plane and there rcbolted to the fixtures 25E and 21, as indicated by the dotted lines. rihe hinge bolts, such as i8, are then retightcned and `the main circuit breaker 4may be closed. With this arrangement, current can now ow from the left hand end of the bus il. through link 14, bridge conducting `nien'iber to the link i5' and back to the left hand end of the bus i2. Accordingly, the secondary windings will new be connected in series. However, as noted in the introduction, knife tarro* ment requires that the link `members which effect srching operation be moved from a first plane of the interleaved bus bars iti, 1l. and 12 to the second plane as indicated by the dotted lines to thereby introduce additional reactance to the bus circuit. Furthermore, considerable time is consumed by the operator in the loosening, removing and tightening of the plurality ol" bolts involved in this arrangement, etc, etc.

The principles of my invention are best illustrated in Figure 2. In this illustration, the bus bars 10, 11, 12 and 13 are inter-leaved in the same manner as the bus bars noted in Figure l. However, the split inner buses 11 and 12 are bridged by bridging contact members 25 and 26 which move in the same plane as that including the bus bars. The bridge contact members 25 and 26 are spring biased away from the inner bus bars 11 and 12. A bridging contact 27 is provided to electrically connect the adiacent bus bars 11 and 12 to each other when it is moved to engaged position by the control unit 28.

In the switch position of Figure 2, the secondary Winding of the transformer are connected in series by the interleaved bus system 10, 11, 12 and 13. However, when the control rod 28 is moved to the right, the bridging engagement of Contact 27 with the bus bars 11 and 12 is disengaged and the cams 29 and 30 move the parallel bridge contacts 25 and 26 into bridging engagement, respectively, with the conductors 11 and 12. Hence, in the second position, when the control rod 28 is moved to the extreme right, the secondary windings will be connectcd in parallel. Thus, the contacts 25 and 26 can be referred to as a parallel contact since their engagement etfects parallel connection of the transformer secondary windings andthe bridging contact 27 can be referred to as a series contact since its engagement will result in the series connection of the transformer secoiidaries.

The wiring diagram of Figure 3 illustrates the electrical connection of the secondary windings 33 and 34 to the furnace terminals by means of my switching apparatus. Figure 3a illustrates the parallel connection of the secondary windings when the parallel bridging contacts 25 and 26 are in engagement and the series bridging contact 27 is disengaged. Figure 3b illustrates the series connection of the secondaries 33 and 34 when the parallel contacts 25 and 26 are disengaged and the series contact 27 is engaged.

Figures 4, 5, 6, 7 and 8 illustrate the physical embodiment of my switching apparatus utilizing the principles set forth in connection with Figures 2 and 3 above.

Each of the switch units 25, 26 and 27, used in the switching apparatus of my invention, may have a plurality of bridging Contact members all controlled from a single operating shaft. The bridging contact members are engaged and disengaged by rotating their operating shafts, such as 30, 31, 32, through an angle of 60.

The switch units used 25, 26 and 27 and the drive mechanism by which they can be controlled from by operating shafts is shown and discribed in my copending application Serial No. 317,101 led October 27, 1952.

Figure 4 illustrates the switch apparatus of my invention in its installed position. The switching apparatus 50 is mounted on the tower unit comprising the plurality of structural members 51. Control means for the operation of the switch units 25, 26 and 27 is illustrated generally at 52. This unit comprises a handle 53 mounted on the rotating shaft 54, which, through gear box 55, controls the rotation of the crank member 56.

The tie link 57 connected to the crank member 56 is connected to the bell crank 58 pivoted at 59 on member 6i). Thus, rotation of the handle 54 will result in substantially vertical movement of the tie link 57 thereby rotating the bell crank 58 about its pivot 59.

The rotation of the bell crank 58, as will hereinafter be more fully described, will result in the switching operation from parallel to series connection and vice versa.

An extension 61 of the crank 53 engages the bottom 62 on the gear box 65. An appropriate means may be provided, as illustrated by the opening 63 in the protrusion 62, to padlock the crank 53 in position illustrated so that the switch units cannot be moved from parallel to series position or vice versa until the padlock is removed. It is desirable to use Kirk key interlocks for the switch apparatus so as to insure that no contacts will be engaged or disengaged until the main circuit breaker has been opened. These interlocks are so arranged that the switch cannot be operated until the key is inserted and turned, and the circuit breaker must be open before the key can be obtained from the breaker. Conversely, the key cannot be removed from the switch handle until the switch operation is completed, and this key must be returned to the circuit breaker before the breaker can be reclosed.

Figures 5, 6, 7, and 8 illustrate the details of the switching apparatus of my invention.

The bus bars 10, 11, 12 and 13 represent one section of the switching apparatus. It will be noted that in the illustration of these gures, the switch apparatus 50 is provided with 16 bus bars which in elfect constitute four units integrated into one switching apparatus. Identical numerical units are used for each unit.

The bus bars 10, 11 and 12 are held in place mechanically by the bolts, washers and nuts, identified by numerals 71 and 72. An insulating shaft may be placed over the bolts 71, 72 to prevent shorting one bus to another.

insulating units 74 are provided for insulation between the plurality of bus bars 10, 11, 12 and 13 etc. The bolts 71 and 72 pass through these insulation units. As best seen in Figure 5a, insulating members 75 are positioned on the outside bus bars to provide for insulation between the outside bus bars and 13 and the grounded frame. The portion of the bus bars between the extreme spacer insulator 74 is spaced and insulated by members 76, as best seen in Figure 8. A bolt 80-81 passes through the bus bars and the insulating members 76. An appropriate insulating sleeve 79 may be provided to insure that adjacent bus bars are not shorted to each other.

It will be noted that the bolt means 78 also provide for attachment and securement of the series switch 27 to the inner adjacent bus bars 11 and 12. In like manner the bolts and 81 respectively secure the parallel switch units 25 and 26 to .the bus bars 11 and 12.

As the switch apparatus 50 is viewed in Figures 5a and 8, the lower portion thereof is connected to the transformer `secondary windings and the upper portion is connected to the furnace. That is, the bus bars 10` and 11 would be connected to the two terminals of one secondary winding and the bus bars 12and 13 to a second secondary winding.

Thus, it will be seen 'that when the bridging contact member 127 of series switch 25 is in engagement with -i-ts stationary contacts 911 and 92 while the parallel switches 25 and `26 :are Idisengaged from the center bus bars 11 :and 12, the .apparatus will be in position to connect the secondary winding in ser-ies. That is, the switch apparatus 50 will be in the series switch position. However, when `the Iswitch uni-ts 25, 26 and 27 assume the position illustrated in Figure 8, the secondary windings will be connected -in parallel.

The `operating shafts 30, 31 and 32 of the three switch units 25, 26 #and 27 lare `in spaced parallel relation to one another. As heretofore noted, ythe single operation of the crank 53, as seen in 4Figure 4, will result in a simultaneous opera-tion of the three switches 25, 26 and -27 of each unit.

The control shafts 30, E311 and 32 extend beyond the height of the bus 'bars I10, 11, -12 and 113, as seen in IFigure 7. The bell crank 58 :is connected by means of clevis member '94 -to the 4link 95. Link 95 1in turn is connected by the clevis 96 to lthe operating shaft 31 of the switch unit 26.

As best `seen in the 'bottom -view of Figure 6, the [portion of the `shaft 31 which extends below the switching apparatus has a gear 103 attached thereto. In like manner, the control shaft 30 :and '32 of the switching units 25 and 27 have gears 102 and 101, respecitvely, connected to the portion thereof extending below the bearing plate 105.

An 'idler gear 100 is also mounted .below the switch to connect driving gear 103 to driven gear 5102. Thus, when the crank 53 is 4rotated so that the clevis 58 is rocked from the solid position to the dotted posi-tion of Figure 7, the control shaft 3.1 will be rotated in 4a counterclockwise direction :as viewed in Figures 5a and 7. This movement will bring bridge member =125 and 126 of parallel switch units `25 and 26 respectively into engagement with their stationary contact 22'5 and 226, respectively. Thus, energy from the handle 53 will be transmitted through the control 'shaft 311 to its associ-ated gear |103. The other parallel switch unit 25 will lbe driven closed by the meshing of the idler rgea-r 100, driven by gear l10.3, with the gear 102 through the medium of the control shaft 30.

The series switch uni-t 27 will be d-riven to the open or disengaged position fby means of energy transmitted through gear 103 to the gear 101 of the shaft 32. Thus, 4this movement of the operating unit or control means 53, 57, 58, 94, 195, `-97 will place the switch apparatus 50 in series switch position as indicated in iFigure `8.

I-t will be noted that a plurality of control cranks or levers 97 :are provided for each section of the switching apparatus and thus, the various sections will operate simultaneously with a single operation of the crank 53. The levers .are attached to -the clevis members 61 by means of threaded portion 101. Hence, the etfective length ofthe links `61, 95', 61 can be properly adjusted and altered to provide for proper adjustment land coordination of the plurality of series and parallel switches.

`lt is noted that each of the shafts V30, 31 and 32 is at the same potential `as its associated switch unit 25, 26, 27 or bus bar ,111, :12 when the switch is in a closed position and hence, it is necessary to not only insulate these shafts 30, l31, 32 from ground `but to lalso insulate them from each others. This is achieved by making the bear-ing 7 plates i104 and 105 at the top 'and bottom, respectively, of the switching `apparatus of insulating material such as a laminated phenolic ymaterial or a pressed dibre and by providing 4a novel `arrangement whereby gears i101, 102 `and 103 will be made from an insulating material.

In addition to these insulation protections, the control links `95 for the operation of the shafts 31 are also made of insulating material to insulate the switch units 25, 26 and 27 from ground. Thus, although the switch units 25, l26 and l27 which rare used in my switching apparatus 'Sii may have the inherent structural arrangement whereby the control shafts 30, 131 land '32 have the same potential 4as the bars 11, 12 to which their respective switches Iare connected, v'all Iof the switch units are insula-ted from each other land from ground by rneans of "the insulating bearing plates 104, 105, the insulating gears 161, 162, 1193 and the insulating link members 95.

It will be noted that the links 95 do not have to be insulating members since the switch units 26 from each section will be at the same potential and hence, `it is not necessary to 'insulate one from the other. However, it is necessary to provide insulation from the `switch units 26 ito ground and this is provided by the insulating link 95, -as best seen in `Figures 4, 5a and 7.

Thus, it will be noted that with the switch apparatus `of my invention, the switch units 25, 26 Iand 27 for each sect-ion of the switch will be isimultaneously operated thereby insuring that change over from series to parallel switch position will take a minimum length `of time thereby reducing the lost production time.

lAlso, since the switch units 25, '26 and 27 have bridging members `125, '126 and 127 `operating within the plane of the plural-ity of bus bars 10, |11, i12 and )13, the switch apparatus in the main 'can be confined to the volume outlined by the bus structure 10, 11, 12 and 13.

'Furthe-r, by insuring that the bridge members 125, i126 and 127 Iremain within the plane of the bus bars, no additional reactance is 'introduced to the switching apparatus '50.

The principles of my invention `can also be lapplied to switch apparatus which has an yopen and closed position rather than a switch from parallel to series connection. Thus, as seen in Figure 9, the bus bars i200 and 201 may be connected and disconnected from the source connected to the top thereof by means of the switch units v263 and 204.

The control of the operation of the switch units '203 through the `clevis 207 and the links 208 is substantially the same as that heretofore described in connection with the series parallel switching apparatus of lFigur-es 2 through 8.

In the foregoing, I have described my invention only in connection with preferred specific embodiments thereof. Many variations :and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, l prefer to be bound not by the specific disclosure herein but only 4by the ap-pending claims.

I claim:

l. ln a switching apparatus for a bus structure cornprising a plurality of discontinuous bus bars and said apparatus having series and parallel switching connections comprising a series switch unit and two parallel switch units; said switch units having a bus bar engaged and a bus bar disengaged position; said series switch unit engaging and bridging some of said bars and said parallel switch units disengaging said bus bars when said switching apparatus is in series connected position; means to simultaneously control said series switch unit and said parallel switch units; said series and parallel switch units being confined within the space deiined by the bus bars of said switching apparatus.

2. A switching apparatus for a bus structure comprising a plurality of discontinuous bus bars and said apparatus having a series and parallel switch position comprising a series switch unit, a first and second parallel switch unit and a plurality of inter-leaved bus bars coinprising atleast a first and second bus bar; said switch units having a bus bar opened and closed position; said series switch unit bridging said first bus bar and said second bus bar when said series switch unit is in bus bar closed position; said first and second parallel switch units bridging a gap respectively in said first and second bus bars when said first and second parallel switch units are iii bus brrr closed position; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved ous bars.

3. A switching apparatus for a bus structure comprisinU a plurality of discontinuous bus bars and said apus having a series and parallel switch position compi ang a series switch unit, a first and second parallel switch unit and a plurality of inter-leaved bus bars coniprising at least a first and second bus bar; said switch units having a bus bar operi and closed position; said series switch unit bridging said first bus bar and said second bus bar when said series switch unit is in bus bar closed position to thereby connect said switching apparatus in said series switch position; said first and second parallel switch units being connected to close a gap respectively in said first and second bus bars when said iirst and second parallel switch units are in bus bar closed position to thereby connect said switching apparatus in said parallel switch position; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved bus bars; and control means for said switch units; said control means simultaneously operating said switch units to a series or parallel connection.

4. A switching apparatus for a bus structure comprising a plurality of discontinuous bus bars and said apparatus having a series and parallel switch position coinprising a series switch unit, two parallel switch units and a plurality of inter-leaved bus bars; said switch units comprising a bridging member having bus bar open and closed position; said series switch unit bridging a first bus bar and a second bus bar of said plurality of bus bars when said switch unit is in bus bar closed position to phase connect said switching apparatus in series switch position; said first and second parallel switch units respectively bridging a gap respectively in said first and second bus bars of said plurality of bus bars when said first and second parallel units are in bus bar closed position 'to thereby connect said switching apparatus in parallel switch position; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved bus bars; control means for said switch units; said control means simultaneously operating said switch units to a series or parallel connection; said operating means interlocked to prevent operation of said switching units when said switching apparatus is energized.

5. A `switching apparatus for a bus structure comprising a plurality of discontinuous bus bars and said apparatus having a series and parallel switch position comprising a series switch unit, two parallel switch units and a plurality of inter-leaved bus bars; said switch units having an engaged and disengaged position; said series switch unit bridging a first bus bar and a second bus bar when said series switch unit is in engaged position; said first and second parallel switch units bridging a gap respectively in said first and second bus bars when said first and second parallel switch units are in engaged position; said series and parallel switch units being confined within the spaced defined by said plurality of inter-leaved bus bars; said switching units having bridging contacts; said bridging contacts for each of said switch units operated from a common operating unit; said operating unit effective to cause disengagement of said parallel switch units while causing engagement of said series switch unit.

6. Switching apparatus for a bus structure comprising a plurality of discontinuous bus bars and said apparatus comprising a first, second, third and fourth inter-leaved bus bars; a first parallel switch unit associated with said first bus bar; a second parallel switch unit associated with said second bus bar; a series,I switch unit associated with said first and second bus bar; said first and second parallel switch unit and said series switch unit confined within the space defined by said first, second, third and fourth inter-leaved bus bars; said first bar positioned adjacent said second bus bar; said third and fourth bus bars straddling said first and second bus bars; each of said switch units being operated from an operating shaft individual thereto; manual control means connected to said operating shaft of said first parallel switch unit; said operating shaft of said first parallel switch unit geared to said operating shafts of said second parallel switch unit and said series switch unit; operation of said manual control means effective to simultaneously operate said switch units.

7. Switching apparatus comprising a first, second, third and fourth inter-leaved bus bars; a first parallel switch unit individual to said first bus bar; a second parallel switch unit individual to said second bus bar; a series switch unit individual to said first and second bus bar; said switch units having a bus bar engaged and a bus bar disengaged position; said first and second parallel switch unit and said series switch unit being confined within the space defined by said first, second, third and fourth inter-leaved bus bars; said first bus bar being positioned adjacent said second bus bar; said third and fourth bus bar respectively positioned adjacent said first and second bus bars; an operating shaft connected to and op` erating each of said 4Switch units; manual control means connected to said operating shaft of said first parallel switch unit; said operating shaft of said first parallel switch unit being geared to said operating shafts of said second parallel switch unit and said series switch unit; operation of said manual control means being effective to simultaneously operate said switch units; said parallel switch units being moved to engaged position by said manual control means when said series switch unit is moved to disengaged position by said manual control means.

8. A switching apparatus having a series and parallel switch position comprising series switch units, parallel switch units, a common operating unit, and has a plurality of inter-leaved discontinuous bus bars; said switching units having bridging contacts; said bridging contacts having a bus bar engaged and bus bar disengaged position; a common operating unit for said bridging contacts of said switch units; said operating unit being effective to cause simultaneous bus bar disengagement of said parallel switch units at the discontinuous bus bars while causing bus bar engagement of said series switch unit; said series switch units connecting adjacent discontinuous bus bars to each other when said series switch unit is moved to bus bar engaged position by said common operating unit; said parallel switch units closed a gap in said adjacent bus bars when said parallel units are moved to bus bar engaged position by said common operating unit; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved discontinuous bus bars.

9. A switching aparatus having a series and parallel switch position comprising series switch units, parallel switch units and buses comprising a plurality of discontinuous inter-leaved bus bars; said switching units having bridging contacts having a bus bar engaged and a bus bar disengaged position; said bridging contacts for each of said switch units being operated from a common operating unit; said operating unit being effective to cause simultaneous bus bar disengagement of said parallel switch units and bus bar engagement of said series switch units to thereby place said switching apparatus in series switch position; said series switch units connecting adjacent bus bars of said plurality of inter-leaved bus bars to each other when said series switch unit is moved to bus bar engaged position; said parallel switch units bridging a gap in each of said adjacent bus bars when said parallel switch units are moved to bus bar engaged position; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved bus bars.

10. A switching apparatus having a series and parallel switch position comprising a series switch unit, parallel switch units and has a plurality of inter-leaved discontinuous bus bars; said switch units having bridging contacts having a bus bar engaged and bus bar disengaged position; a common operating unit for said bridging contacts of said switch units; said common operating unit being effective to cause a simultaneous bus bar disengagernent of said parallel switch units at the discontinuous portions of said bus bars and bus bar engagement of said series switch units to thereby place said switching apparatus in series switch position; said series switch unit connecting adjacent discontinuous bus bars of said plurality of inter-leaved bus bars to each other when said series switch unit is moved to bus bar engaged position; said parallel switch units bridging a gap in each of said adjacent bus bars when said parallel switch units are moved to bus bar engaged position; said series and parallel Switch units being confined within the space defined by said plurality of inter-leaved bus bars; said common operating unit being effective to position said switching apparatus in parallel switch position by simultaneously moving said parallel switch units to bus bar engaged position and said series switch unit to bus bar disengaged position.

ll. A switching apparatus having a series and parallel switch position comprising series switch unit, parallel switch units and a plurality of discontinuous inter-leaved bus bars; said switch units having a bus bar engaged and a bus bar disengaged position; said series switch unit electrically connecting adjacent bus bars to each other at their discontinuous portion when said series switch unit is in bus bar engaged position; said parallel switch units bridging a gap in each of said adjacent discontinuous bus bars when said parallel switch units are in bus bar engaged position; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved bus bars; said switching units having bridging contacts bridging the 'discontinuous portions of the bus bars, a common operating unit for said bridging contacts of said switch units; said common operating unit being effective to cause disengagement of said parallel switch units and effect engagement of said series switch unit to thereby place said switching apparatus in series switch position.

l2. A switching apparatus having a series and parallel switch position comprising series switch unit, parallel switch units and a bus comprising a plurality of Adiscontinuous inter-leaved bus bars; said switch units having a bus bar engaged and a bus bar disengaged position; said series switch unit electrically connecting adjacent bus bars to each other when said series switch unit is in bus bar engaged position; said parallel switch units bridging a gap in each of said adjacent bus bars at their discontinuous portions when said parallel switch units are in bus bar engaged position; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved bus bars; said switching units having bridging contacts; a common operating unit connected to and operating said bridging contacts of said switch units; said common operating unit being effective to simultaneously move said parallel switch units to bus bar engaged position and said series switch unit to bus bar disengaged position to thereby place said switching apparatus in parallel switch position.

13. A switching apparatus having a series and parallel switch position comprising a series switch unit, parallel switch units and buses comprising a plurality of interleaved bus bars, insulated from each other, certain of the bus bars having discontinuous portions, alternate bus bars carrying current in one direction and the remaining alternate bus bars carrying the current in the opposite direction; said switch units each having a bus bar engaging and a bus bar disengaged position; said series switch unit bridging said discontinuous portions of the bus bars to connect adjacent bus bars to each other when said series switch unit is in bus bar engaged position; said parallel switch units bridging said discontinuous portions of the adjacent bus bars when said parallel switch '..mits are in bus bar engaged position; said series and parallel switch units being confined within the space defined by said plurality of inter-leaved bus bars; said switching units having bus bar bridging contacts; a common operating unit connected to and operating said bridging contacts of said switch units; said common operating unit being effective to cause bus bar disengagement of said parallel switch units and cause bus bar engagement of said series switch unit to thereby place said switching apparatus in series switch position; said common operating unit being effective to simultaneously move said parallel switch units to bus bar engaged position and said series switch unit to bus bar disengaged position to thereby place said switching apparatus in parallel switch position.

lll. in a switching apparatus, a plurality of inter-leaved bus bars in spaced parallel arrangement, some of said bus bars being in axial alignment with other of said bus bars, said bus bars insulated from each other and occupying a predetermined space, a switching mechanism for selectively connecting said bus bars in parallel and in series comprising first and second bridging switches mounted within the confines of the space of said bus bars, a first means for operating said first bridging switch to bridging positions in which said first bridging switches engage and bridge within adjacent axially aligned bus bars, said second bridging switch mounted within the confines of the space of said bus, a second means for operating said second bridging switch to bridging position in which said second bridging switch engages and bridges between adjacent parallel bus bars.

l5. In a switch apparatus, a plurality of inter-leaved bus bars in spaced parallel arrangement, some of said bus bars being in axial alignment with other of said bus bars, extensions from said parallel bus bars, said bus bars insulated from each other and occupying a predetermined space, a switching mechanism for selectively connecting said bus bars in parallel circuits and in straight line series circuits comprising first and second bridging switches mounted within the confines of the space of said bus bars, a first means for operating said first switches to bridging positions in which said first switches engage and bridge within adjacent axially aligned bus bars, said second bridging switch mounted within the confines of the space of said buses, a second means operating said second switches to bridging positions in which said second switches engage and bridge said extensions for electrically connecting between adjacent parallel bus bars, and a common operating mechanism for said first and second l6. ln a switching apparatus, a plurality of inter-leaved bus bars in spaced parallel arrangement, some of said bus bars being in axial alignment with other of said bus bars, extensions from said parallel bus bars, said bus bars insulated from each other and occupying a predetermined spaced, a switching mechanism for selectively connecting said bus bars in parallel circuits and in straight line series circuits comprising first and second bridging switches mounted within the confines of the space of said bus bars, means for operating said first switch to bridging positions in which said first switch is brought into wiping engagement with and bridges within adjacent axially aligned bus bars, said means operating said second switch to bridging position in which said second switch is brought into wiping engagement with and bridges said extensions between adjacent parallel bus bars.

17. In a switching apparatus, a plurality of inter-leaved bus bars in spaced parallel arrangement, some of said bus bars being in axial alignment with other of said bus bars, extensions from said parallel bus bars, said bus bars insulated from each other and occupying a predetermined space, a switching mechanism for selectively connecting said bus bars in parallel circuits and in straight line series circuits comprising first and second bridging switch mounted within the confines of the space of said bus bars, said first and second switches having bus bar engaging surfaces, means for operating said first switches to bridging positions in which said first switches are brought into wiping engagement with and bridge within adjacent axially aligned bus bars, said means operating said second switch to bridging positions in which said second switch is brought into wiping engagement with and bridges between said extensions for electrically connecting adjacent parallel bus bars.

References Cited in the file of this patent UNITED STATES PATENTS 

